“We’re confident that the Department of Justice understands that the First Amendment protects all American citizens and that it would not participate in such a blatant abuse of government power,” the newspaper said.

Trump has raged to confidantes that a "deep state" within his administration is conspiring against him. He has ordered aides to unmask the writer, as his top officials issued a string of denials.

Secretary of State Mike Pompeo and Secretary of Defense Jim Mattis denied authorship on a visit to India; Interior Secretary Ryan Zinke chimed in from American Samoa. In Washington, the claims of "not me" echoed from Vice President Pence's office, from Energy Secretary Rick Perry, from Ambassador to Russia Jon Huntsman from Dan Coats, director of national intelligence, and other Cabinet members.

Former New York mayor Rudy Giuliani, now the President's attorney, suggested that it “would be appropriate” for Trump to ask for a formal investigation into the identity of the op-ed author.

"Let's assume it's a person with a security clearance. If they feel writing this is appropriate, maybe they feel it would be appropriate to disclose national security secrets, too. That person should be found out and stopped," Giuliani told the Associated Press.